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The Milky Way’s supermassive black hole: how good a case is it? A challenge for astrophysics & philosophy of science. (English) Zbl 1373.83004

This review paper carefully describes and analyzes the arguments that can lead to the notion of a black hole and its possible observation. It has 330 references from mathematical, astronomical, physical, historical and philosophical sources. After a nice introduction, Section 2 deals with the concept of black holes, both in general relativity and in quantum theory. It presents several variants of the black hole uniqueness theorem. Section 3 covers philosophical issues like underdetermination and the Eleatic principle. Section 4 is on observations, and Section 5 discusses alternatives to the black hole scenario.
From the authors’s summary: “The compact and …very massive object located at the center of the Milky Way is currently the very best candidate for a supermassive black hole (SMBH) in our immediate vicinity. The strongest evidence for this is provided by measurements of stellar orbits, variable X-ray emission, and strongly variable polarized near-infrared emission from the location of the radio source Sagittarius A* (SgrA*) in the middle of the central stellar cluster. Simultaneous near-infrared and X-ray observations of SgrA* have revealed insights into the emission mechanisms responsible for the powerful near-infrared and X-ray flares from within a few tens to one hundred Schwarzschild radii of such a putative SMBH. If SgrA* is indeed a SMBH it will, in projection onto the sky, have the largest event horizon and will certainly be the first and most important target for very long baseline interferometry observations currently being prepared by the event horizon telescope (EHT). These observations in combination with the infrared interferometry experiment GRAVITY at the very large telescope interferometer and other experiments across the electromagnetic spectrum might yield proof for the presence of a black hole at the center of the Milky Way. The large body of evidence continues to discriminate the identification of SgrA* as a SMBH from alternative possibilities. It is, however, unclear when the ever mounting evidence for SgrA* being associated with a SMBH will suffice as a convincing proof ….
This manuscript reviews the observational facts, theoretical grounds and conceptual aspects for the case of SgrA* being a black hole. We treat theory and observations in the framework of the philosophical discussions about (anti)realism and underdetermination.”

MSC:

83-02 Research exposition (monographs, survey articles) pertaining to relativity and gravitational theory
85-02 Research exposition (monographs, survey articles) pertaining to astronomy and astrophysics
83C57 Black holes
00A79 Physics
03A05 Philosophical and critical aspects of logic and foundations
85A15 Galactic and stellar structure
83C22 Einstein-Maxwell equations
83C10 Equations of motion in general relativity and gravitational theory
83-03 History of relativity and gravitational theory
01A60 History of mathematics in the 20th century
01A55 History of mathematics in the 19th century
83C47 Methods of quantum field theory in general relativity and gravitational theory
81T20 Quantum field theory on curved space or space-time backgrounds
53Z05 Applications of differential geometry to physics
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References:

[1] Aasi, J., Abadie, J., Abbott, B.P., Abbott, R., Abbott, T., Abernathy, M.R., Accadia, T., Acernese, F., Adams, C., Adams, T., et al.: Directed search for continuous gravitational waves from the Galactic center. Phys. Rev. D 88(10), 102002 (2013). arXiv:1309.6221 · doi:10.1103/PhysRevD.88.102002
[2] Aasi, J., Abbott, B.P., Abbott, R., Abbott, T., Abernathy, M.R., Acernese, F., Ackley, K., Adams, C., Adams, T., Addesso, P., et al.: Search for gravitational wave ringdowns from perturbed intermediate mass black holes in LIGO-Virgo data from 2005-2010. Phys. Rev. D 89(10), 102006 (2014). arXiv:1403.5306 · doi:10.1103/PhysRevD.89.102006
[3] Abbott, B.P., Abbott, R., Abbott, T.D., Abernathy, M.R., Acernese, F., Ackley, K.: Observation of gravitational waves from a binary black hole merger. Phys. Rev. Lett. 116, 061102 (2016). doi:10.1103/PhysRevLett.116.061102 · doi:10.1103/PhysRevLett.116.061102
[4] Abdolrahimi, S., Mann, R.B., Tzounis, C.: Distorted local shadows. Phys. Rev. D 91(8), 084052 (2015) · doi:10.1103/PhysRevD.91.084052
[5] Abramowicz, M.A., Kluźniak, W., Lasota, J.P.: No observational proof of the black-hole event-horizon. A&A 396, L31-L34 (2002). arXiv:astro-ph/0207270 · Zbl 1025.83503 · doi:10.1051/0004-6361:20021645
[6] Amaro-Seoane, P., Gair, J.R., Freitag, M., Miller, M.C., Mandel, I., Cutler, C.J., Babak, S.: Topical review: intermediate and extreme mass-ratio inspirals astrophysics, science applications and detection using LISA. Class. Quantum Gravity 24, R113-R169 (2007) · Zbl 1128.85300 · doi:10.1088/0264-9381/24/17/R01
[7] Amaro-Seoane, P., Aoudia, S., Babak, S., et al.: Low-frequency gravitational-wave science with ELISA/NGO. Class. Quantum Gravity 29(12), 124016 (2012) · doi:10.1088/0264-9381/29/12/124016
[8] Anderl, S.: Astronomy and astrophysics in the philosophy of science. (2015). arXiv:1510.03284
[9] Anderl, S.: Astronomy and Astrophysics. In: Humphreys, P. (ed.) The Oxford Handbook of Philosophy of Science. Oxford University Press, Oxford (2016). doi:10.1093/oxfordhb/9780199368815.013.45
[10] Arca-Sedda, M.: On the formation of compact, massive subsystems in stellar clusters and its relation with intermediate-mass black holes. MNRAS 455, 35-50 (2016). arXiv:1502.01242
[11] Armstrong, D. (ed.): A World of States of Affairs, p. 41. Cambridge University Press, Cambridge (2001). ISBN-13:9780521580649, ISBN-10:0521580641
[12] Baganoff, F.K., Bautz, M.W., Brandt, W.N., Chartas, G., Feigelson, E.D., Garmire, G.P., Maeda, Y., Morris, M., Ricker, G.R., Townsley, L.K., Walter, F.: Rapid X-ray flaring from the direction of the supermassive black hole at the Galactic centre. Nature 413, 45-48 (2001) · doi:10.1038/35092510
[13] Baganoff, F.K., Maeda, Y., Morris, M., Bautz, M.W., Brandt, W.N., Cui, W., Doty, J.P., Feigelson, E.D., Garmire, G.P., Pravdo, S.H., Ricker, G.R., Townsley, L.K.: Chandra X-ray spectroscopic imaging of Sagittarius A* and the central parsec of the galaxy. ApJ 591, 891-915 (2003) · doi:10.1086/375145
[14] Bahcall, J.N., Wolf, R.A.: Star distribution around a massive black hole in a globular cluster. ApJ 209, 214-232 (1976) · doi:10.1086/154711
[15] Balick, B., Brown, R.L.: Intense sub-arcsecond structure in the galactic center. ApJ 194, 265-270 (1974) · doi:10.1086/153242
[16] Barbour, J.B., Pfister, H. (eds.): Mach’s Principle: From Newton’s Bucket to Quantum Gravity. Birkhäuser, Boston (1995). ISBN 978-0-8176-3823-8 · Zbl 0846.01008
[17] Bardeen, J.M.: Rapidly rotating stars, disks, and black holes. In: DeWitt, C., DeWitt, B.S. (eds.) Black Holes (Les Astres Occlus), pp. 241-289 (1973) · Zbl 1025.83503
[18] Bardeen, JM; Wagoner, RV, No article title, Relativistic disks. I. Uniform rotation. ApJ, 167, 359 (1971)
[19] Barrau, A., Rovelli, C., Vidotto, F.: Fast radio bursts and white hole signals. Phys. Rev. D 90(12), 127503 (2014) · doi:10.1103/PhysRevD.90.127503
[20] Barrau, A., Bolliet, B., Schutten, M., Vidotto, F.: Bouncing black holes in quantum gravity and the Fermi gamma-ray excess. (2016). arXiv:1606.08031 · Zbl 1421.83063
[21] Barrière, N.M., Tomsick, J.A., Baganoff, F.K., Boggs, S.E., Christensen, F.E., Craig, W.W., Dexter, J., Grefenstette, B., Hailey, C.J., Harrison, F.A., Madsen, K.K., Mori, K., Stern, D., Zhang, W.W., Zhang, S., Zoglauer, A.: NuSTAR detection of high-energy X-ray emission and rapid variability from Sagittarius A* flares. ApJ 786, 46 (2014). arXiv:1403.0900 · doi:10.1088/0004-637X/786/1/46
[22] Bartusiak, M.: Black Hole. Yale University Press, New Haven (2015). ISBN 9780300210859 · Zbl 1322.83001
[23] Berti, E., Barausse, E., Cardoso, V., Gualtieri, L., Pani, P., Sperhake, U., Stein, L.C., Wex, N., Yagi, K., Baker, T., Burgess, C.P., Coelho, F.S., Doneva, D., De Felice, A., Ferreira, P.G., Freire, P.C.C., Healy, J., Herdeiro, C., Horbatsch, M., Kleihaus, B., Klein, A., Kokkotas, K., Kunz, J., Laguna, P., Lang, R.N., Li, T.G.F., Littenberg, T., Matas, A., Mirshekari, S., Okawa, H., Radu, E., O’Shaughnessy, R., Sathyaprakash, B.S., Van Den Broeck, C., Winther, H.A., Witek, H., Emad Aghili, M., Alsing, J., Bolen, B., Bombelli, L., Caudill, S., Chen, L., Degollado, J.C., Fujita, R., Gao, C., Gerosa, D., Kamali, S., Silva, H.O., Rosa, J.G., Sadeghian, L., Sampaio, M., Sotani, H., Zilhao, M.: Testing general relativity with present and future astrophysical observations. Class. Quantum Gravity 32(24), 243001 (2015) · Zbl 0020.28501
[24] Berti, E., Sesana, A., Barausse, E., Cardoso, V., Belczynski, K.: Spectroscopy of Kerr Black Holes with Earth- and Space-based interferometers. Phys. Rev. Lett. 117(10), 101102 (2016) · doi:10.1103/PhysRevLett.117.101102
[25] Bethge, K., Gruber, G., Stöhlker, T. (eds.): Physik der Atome und Moleküle: Eine Einfhrung, p. 4445. Wiley, New York (2012). ISBN 978-3-527-66255-5
[26] Bilic, N., Tupper, G.B., Viollier, R.D.: Supermassive fermion balls and constraints from stellar dynamics near Sgr A*. Astrophysics (2003). arXiv:astro-ph/0310172 · Zbl 0022.28104
[27] Bird, S., Cholis, I., Muñoz, J.B., Ali-Haïmoud, Y., Kamionkowski, M., Kovetz, E.D., Raccanelli, A., Riess, A.G.: Did LIGO detect dark matter? Phys. Rev. Lett. (2016). arXiv:1603.00464
[28] Blais, D., Kiefer, C., Polarski, D.: Can primordial black holes be a significant part of dark matter? Phys. Lett. B 535, 11-16 (2002). arXiv:astro-ph/0203520 · doi:10.1016/S0370-2693(02)01803-8
[29] Blandford, R.D., Begelman, M.C.: On the fate of gas accreting at a low rate on to a black hole. MNRAS 303, L1-L5 (1999). arXiv:astro-ph/9809083 · doi:10.1046/j.1365-8711.1999.02358.x
[30] Boehle, A., Ghez, A.M., Schödel, R., Meyer, L., Yelda, S., Albers, S., Martinez, G.D., Becklin, E.E., Do, T., Lu, J.R., Matthews, K., Morris, M.R., Sitarski, B., Witzel, G.: An improved distance and mass estimate for Sgr A* from a multistar orbit analysis. ApJ 830, 17 (2016). arXiv:1607.05726
[31] Bogdanović, T.: Supermassive Black Hole Binaries: The Search Continues. In: Astrophysics and Space Science Proceedings, vol. 40, p. 103 (2015). arXiv:1406.5193
[32] Branham, R.L.: The distance to the Galactic center determined by OB stars. Ap&SS 353, 179-190 (2014) · doi:10.1007/s10509-014-2005-9
[33] Britzen, S., Eckart, A., Lämmerzahl, C., et al.: Jet signatures of black holes: from Sgr A* to active galactic nuclei. Astronomische Nachrichten 5(2015), 471-476 (2015) · doi:10.1002/asna.201512178
[34] Broderick, A.E., Loeb, A.: Imaging bright-spots in the accretion flow near the black hole horizon of Sgr A*. MNRAS 363, 353-362 (2005). arXiv:astro-ph/0506433 · doi:10.1111/j.1365-2966.2005.09458.x
[35] Broderick, A.E., Loeb, A.: Imaging optically-thin hotspots near the black hole horizon of Sgr A* at radio and near-infrared wavelengths. MNRAS 367, 905-916 (2006). arXiv:astro-ph/0509237 · doi:10.1111/j.1365-2966.2006.10152.x
[36] Broderick, A.E., Narayan, R.: Where are all the gravastars? Limits upon the gravastar model from accreting black holes. Class. Quantum Gravity 24, 659-666 (2007). arXiv:gr-qc/0701154 · Zbl 1206.83095
[37] Broderick, A.E., Johannsen, T., Loeb, A., Psaltis, D.: Testing the no-hair theorem with event horizon telescope observations of Sagittarius A*. ApJ 784, 7 (2014) · doi:10.1088/0004-637X/784/1/7
[38] Broderick, A.E., Narayan, R., Kormendy, J., Perlman, E.S., Rieke, M.J., Doeleman, S.S.: The event horizon of M87. ApJ 805, 179 (2015) · doi:10.1088/0004-637X/805/2/179
[39] Brown, E.: Ann E. Ewing, 89, Washington Post, Sunday, August 1, 2010, p. 39, (2010). http://www.washingtonpost.com/ wp-dyn/content/article/
[40] Buchholz, R.M., Schödel, R., Eckart, A.: Composition of the galactic center star cluster. Population analysis from adaptive optics narrow band spectral energy distributions. A&A 499, 483-501 (2009). arXiv:0903.2135
[41] Bursa, M., Abramowicz, M.A., Karas, V., Kluźniak, W., Schwarzenberg-Czerny, A.: The timescale of encircling light. In: Hledík, S., Stuchlík, Z. (eds.) Proceedings of RAGtime 8/9: Workshops on Black Holes and Neutron Stars, pp. 21-25 (2007)
[42] Calmet, X.: Quantum Aspects of Black Holes. Springer, Heidelberg (2015). ISBN 978-3-319-10852-0 · Zbl 1305.81003 · doi:10.1007/978-3-319-10852-0
[43] Cardoso, V., Crispino, L.C.B., Macedo, C.F.B., Okawa, H., Pani, P.: Light rings as observational evidence for event horizons: long-lived modes, ergoregions and nonlinear instabilities of ultracompact objects. Phys. Rev. D 90(4), 044069 (2014) · doi:10.1103/PhysRevD.90.044069
[44] Cardoso, V., Franzin, E., Pani, P.: Is the gravitational-wave ringdown a probe of the event horizon? Phys. Rev. Lett. 116(171101), 116 (2016)
[45] Carnap, R.: Logische Syntax der Sprache (1968). ISBN 978-3-662-25376-2(e-book), ISBN 978-3-662-23331-3; 1934 by Julius Springer, 2. Auflage · JFM 60.0019.02
[46] Chakravartty, A.: A Metaphysics for Scientific Realism: Knowing the Unobservable (2010) ISBN 978-0-521-13009-7; 2015 Paperback: ISBN-10: 1508932867, ISBN-13: 978-1508932864
[47] Chandrasekhar, S.: The mathematical theory of black holes. Oxford University Press · Zbl 0511.53076
[48] Chapline G (2003) Quantum Phase Transitions and the Failure of Classical General Relativity. International Journal of Modern Physics A 18:3587-3590, gr-qc/0012094 · Zbl 1339.83044
[49] Christodoulou, M., Rovelli, C., Speziale, S., Vilensky, I.: Planck star tunneling time: An astrophysically relevant observable from background-free quantum gravity. Phys. Rev. D 94(8), 084035 (2016) · doi:10.1103/PhysRevD.94.084035
[50] Clavel, M., Terrier, R., Goldwurm, A., Morris, M.R., Ponti, G., Soldi, S., Trap, G.: Echoes of multiple outbursts of Sagittarius A revealed by Chandra. A&A 558, A32 (2013). 1307.3954
[51] Cleland, C.: Living with the abstract: realism and models. Philosophy of Science 69, 474-496 (2002) · doi:10.1086/342455
[52] Colbert, E.J.M., Mushotzky, R.F.: The Nature of Accreting Black Holes in Nearby Galaxy Nuclei. ApJ 519, 89-107 (1999). astro-ph/9901023 · doi:10.1086/307356
[53] Colpi, M., Shapiro, S.L., Wasserman, I.: Boson stars - Gravitational equilibria of self-interacting scalar fields. Phys. Rev. Lett. 57, 2485-2488 (1986) · doi:10.1103/PhysRevLett.57.2485
[54] Colyvan, M.: Can the eleatic principle be justified? Canad. J. Philos. 28, 313-335 (1998) · doi:10.1080/00455091.1998.10715975
[55] Colyvan, M.: The Indispensability of Mathematics; Oxford University Press, Oxford (2001)(1983). ISBN 0-19-513754-X · Zbl 1078.00500
[56] Contini, M.: The low-luminosity active galactic nucleus in the centre of the Galaxy. MNRAS 418, 1935-1947 (2011). arXiv:1104.1282 · doi:10.1111/j.1365-2966.2011.19612.x
[57] Cumpa, J.; Tegtmeier, E.; Cumpa, J. (ed.); Tegtmeier, E. (ed.), Phenomenological Realism Versus Scientific Realism (2009), Heusenstamm
[58] Cunha, P.V.P., Herdeiro, C.A.R., Radu, E., Rúnarsson, H.F.: Shadows of Kerr Black Holes with Scalar Hair. Phys. Rev. Lett. 115(21), 211102 (2015). arXiv:1509.00021 · Zbl 1347.83020
[59] Danzmann, K.: ELISA and the Gravitational Universe. In: IAU General Assembly , vol. 22, p. 2248153 (2015)
[60] De Paolis, F., Ingrosso, G., Nucita, A.A., Orlando, D., Capozziello, S., Iovane, G.: Astrophysical constraints on a possible neutrino ball at the Galactic Center. A&A 376, 853-860 (2001). arXiv:astro-ph/0107497 · doi:10.1051/0004-6361:20010929
[61] Deccock, L., Horsten, L.: Quine, Naturalized Epistemology, Perceptual Knowledge and Ontology. In: Lieven, D., Leon, H. (eds.). Editions Rodopi B.V. Amsterdam, Atlanta, GA (2000). ISBN 90-420-1241-2
[62] Dékány, I., Minniti, D., Catelan, M., Zoccali, M., Saito, R.K., Hempel, M., Gonzalez, O.A.: VVV survey near-infrared photometry of known bulge RR lyrae stars: the distance to the galactic center and absence of a barred distribution of the metal-poor population. ApJL 776, L19 (2013) · doi:10.1088/2041-8205/776/2/L19
[63] DeWitt C, DeWitt BS (1973) Black holes. In: DeWitt, C., DeWitt, B.S. (eds.)Lectures Delivered at the Summer School of Theoretical Physics of the University of Grenoble at Les Houches. Gordon and Breach, New York · Zbl 0125.27406
[64] Dexter, J., Fragile, P.C.: Tilted black hole accretion disc models of Sagittarius A*: time-variable millimetre to near-infrared emission. MNRAS 432, 2252-2272 (2013) · doi:10.1093/mnras/stt583
[65] Dexter, J., O’Leary, R.M.: The peculiar pulsar population of the central parsec. ApJL 783, L7 (2014) · doi:10.1088/2041-8205/783/1/L7
[66] Dexter, J., Agol, E., Fragile, P.C., McKinney, J.C.: The submillimeter bump in Sgr A* from relativistic MHD simulations. ApJ 717, 1092-1104 (2010) · doi:10.1088/0004-637X/717/2/1092
[67] Dexter, J., Agol, E., Fragile, P.C., McKinney, J.C.: Radiative models of Sagittarius A* and M87 from relativistic MHD simulations. J. Phys. Conf. Ser. 372(1), 012023 (2012a). 1202.0348 · doi:10.1088/1742-6596/372/1/012023
[68] Dexter, J., McKinney, J.C., Agol, E.: The size of the jet launching region in M87. MNRAS 421, 1517-1528 (2012b). arXiv:1109.6011
[69] Do, T., Ghez, A.M., Morris, M.R., Lu, J.R., Matthews, K., Yelda, S., Larkin, J.: High angular resolution integral-field spectroscopy of the galaxy’s nuclear cluster: a missing stellar cusp? ApJ 703, 1323-1337 (2009). arXiv:0908.0311
[70] Do, T., Martinez, G.D., Yelda, S., Ghez, A., Bullock, J., Kaplinghat, M., Lu, J.R., Peter, A.H.G., Phifer, K.: Three-dimensional stellar kinematics at the galactic center: measuring the nuclear star cluster spatial density profile, black hole mass, and distance. ApJL 779, L6 (2013) · doi:10.1088/2041-8205/779/1/L6
[71] Dobler, G., Finkbeiner, D.P., Cholis, I., Slatyer, T., Weiner, N.: The fermi haze: a gamma-ray counterpart to the microwave haze. ApJ 717, 825-842 (2010). arXiv:0910.4583
[72] Doeleman, S.S., Lonsdale, C.J., Greenhill, L.J.: VLBI imaging of the 86 GHz SiO maser emission in the circumstellar envelope of VX sagittarii. ApJ 494, 400-408 (1998) · doi:10.1086/305199
[73] Doeleman, S.S., Weintroub, J., Rogers, A.E.E., Plambeck, R., Freund, R., Tilanus, R.P.J., Friberg, P., Ziurys, L.M., Moran, J.M., Corey, B., Young, K.H., Smythe, D.L., Titus, M., Marrone, D.P., Cappallo, R.J., Bock, D.C.J., Bower, G.C., Chamberlin, R., Davis, G.R., Krichbaum, T.P., Lamb, J., Maness, H., Niell, A.E., Roy, A., Strittmatter, P., Werthimer, D., Whitney, A.R., Woody, D.: Event-horizon-scale structure in the supermassive black hole candidate at the galactic centre. Nature 455, 78-80 (2008) · doi:10.1038/nature07245
[74] Doeleman, S.S., Fish, V.L., Broderick, A.E., Loeb, A., Rogers, A.E.E.: Detecting flaring structures in Sagittarius A* with high-frequency VLBI. ApJ 695, 59-74 (2009) · doi:10.1088/0004-637X/695/1/59
[75] Dvali, G., Gomez, C.: Black Hole’s Quantum N-Portrait. (2011). FortschPhys. 61 742-767 (2013) arXiv:1112.3359 · Zbl 1338.83071
[76] Dvali, G., Gomez, C.: Black hole’s 1/N hair. Phys. Lett. B 719, 419-423 (2013). arXiv:1203.6575 · Zbl 1370.83046
[77] Dvali, G., Gomez, C., Lüst, D.: Black hole quantum mechanics in the presence of species. Fortsch. Phys. 61(7-8), 768-778 (2013). arXiv:1206.2365 · Zbl 1338.83072
[78] Dvali, G., Gomez, C., Lüst, D.: Classical limit of black hole quantum N-portrait and BMS symmetry. Phys. Lett. B 753, 173-177 (2016). arXiv:1509.02114 · Zbl 1367.83044
[79] Earnshaw, H.M., Roberts, T.P., Heil, L.M., Mezcua, M., Walton, D.J., Done, C., Harrison, F.A., Lansbury, G.B., Middleton, M.J., Sutton, A.D.: A variable ULX and possible IMBH candidate in M51a. MNRAS 456, 3840-3854 (2016). arXiv:1512.04825
[80] Eatough, R., Lazio, T.J.W., Casanellas, J., Chatterjee, S., Cordes, J.M., Demorest, P.B., Kramer, M., Lee, K.J., Liu, K., Ransom, S.M., Wex, N.: Observing radio pulsars in the galactic centre with the square kilometre array. Advancing Astrophysics with the Square Kilometre Array (AASKA14), vol. 45 (2015). arXiv:1501.00281
[81] Eatough, R.P., Falcke, H., Karuppusamy, R., Lee, K.J., Champion, D.J., Keane, E.F., Desvignes, G., Schnitzeler, D.H.F.M., Spitler, L.G., Kramer, M., Klein, B., Bassa, C., Bower, G.C., Brunthaler, A., Cognard, I., Deller, A.T., Demorest, P.B., Freire, P.C.C., Kraus, A., Lyne, A.G., Noutsos, A., Stappers, B., Wex, N.: A strong magnetic field around the supermassive black hole at the centre of the Galaxy. Nature 501, 391-394 (2013). arXiv:1308.3147
[82] Eckart, A., Genzel, R.: Observations of stellar proper motions near the Galactic Centre. Nature 383, 415-417 (1996) · doi:10.1038/383415a0
[83] Eckart, A., Genzel, R.: Stellar proper motions in the central 0.1 PC of the galaxy. MNRAS 284, 576-598 (1997) · doi:10.1093/mnras/284.3.576
[84] Eckart, A., Genzel, R., Ott, T., Schödel, R.: Stellar orbits near Sagittarius A*. MNRAS 331, 917-934 (2002) · doi:10.1046/j.1365-8711.2002.05237.x
[85] Eckart, A., Moultaka, J., Viehmann, T., Straubmeier, C., Mouawad, N., Genzel, R., Ott, T., Schödel, R., Baganoff, F.K., Morris, M.R.: Monitoring Sagittarius A* in the MIR with the VLT. Astron. Nachr. Suppl. 324, 557-561 (2003) · doi:10.1002/asna.200385058
[86] Eckart, A., Schödel, R., Straubmeier, C.: The black hole at the center of the Milky Way / Andreas Eckart, Rainer Schödel, Christian Straubmeier. Imperial College Press, London (2005)
[87] Eckart, A., Baganoff, F.K., Schödel, R., Morris, M., Genzel, R., Bower, G.C., Marrone, D., Moran, J.M., Viehmann, T., Bautz, M.W., Brandt, W.N., Garmire, G.P., Ott, T., Trippe, S., Ricker, G.R., Straubmeier, C., Roberts, D.A., Yusef-Zadeh, F., Zhao, J.H., Rao, R.: The flare activity of Sagittarius A*. New coordinated mm to X-ray observations. A&A 450, 535-555 (2006a) · doi:10.1051/0004-6361:20054418
[88] Eckart, A., Schödel, R., Meyer, L., Trippe, S., Ott, T., Genzel, R.: Polarimetry of near-infrared flares from Sagittarius A*. A&A 455, 1-10 (2006b) · doi:10.1051/0004-6361:20064948
[89] Eckart, A., Schödel, R., Straubmeier, C., Bertram, T., Pott, J.U., Muzic, K., Meyer, L., Moultaka, J., Viehmann, T., Rost, S., Herbst, T.: Interferometric observations of the galactic center: LBT and VLTI. In: Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, vol. 6268 (2006c)
[90] Eckart, A., Zamaninasab, M., Straubmeier, C., Fischer, S., Araujo-Hauck, C., Garcia-Marin, M., Wiest, M., Witzel, G., Buchholz, R.M., Sabha, N., Muzic, K., Eisenhauer, F., Paumard, T., Yazici, S., Perrin, G., Brandner, W., Perraut, K., Amorim, A., Schöller, M.: Signatures of strong gravity with GRAVITY. In: Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, vol . 7734 (2010)
[91] Eckart, A., Britzen, S., Horrobin, M., Zamaninasab, M., Muzic, K., Sabha, N., Shahzamanian, B., Yazici, S., Moser, L., Zuther, J., Garcia-Marin, M., Valencia-S, M., Bursa, M., Karssen, G., Karas, V., Jalali, B., Vitale, M., Bremer, M., Fischer, S., Smajic, S., Rauch, C., Kunneriath, D., Moultaka, J., Straubmeier, C., Rashed, Y.E., Iserlohe, C., Busch, G., Markakis, K., Borkar, A., Zensus, A.J.: The Galactic Center as a pradigm for low-luminosity nuclei? What can be learned from SgrA* for the central engine and conditions of star formation in nuclei of Seyfert galaxies and low luminosity nearby QSOs. The K-band identification of the DSO/G2 source from VLT and Keck data. In: Proceedings of Nuclei of Seyfert galaxies and QSOs—Central Engine and Conditions of Star Formation (Seyfert 2012), 6-8 November, 2012. Max-Planck-Insitut fuer Radioastronomie (MPIfR), Bonn, Germany (2012a). arXiv:1311.2743
[92] Eckart, A., García-Marín, M., Vogel, S.N., Teuben, P., Morris, M.R., Baganoff, F., Dexter, J., Schödel, R., Witzel, G., Valencia-S, M., Karas, V., Kunneriath, D., Straubmeier, C., Moser, L., Sabha, N., Buchholz, R., Zamaninasab, M., Mužić, K., Moultaka, J., Zensus, J.A.: Millimeter to X-ray flares from Sagittarius A*. A&A 537, A52 (2012b) · doi:10.1051/0004-6361/201117779
[93] Eckart, A., García-Marín, M., Vogel, S.N., Teuben, P., Morris, M.R., Baganoff, F., Dexter, J., Schödel, R., Witzel, G., Valencia-S, M., Karas, V., Kunneriath, D., Straubmeier, C., Moser, L., Sabha, N., Buchholz, R., Zamaninasab, M., Mužić, K., Moultaka, J., Zensus, J.A.: Millimeter to X-ray flares from Sagittarius A*. A&A 537, A52 (2012c) · doi:10.1051/0004-6361/201117779
[94] Eckart, A., Sabha, N., Witzel, G., Straubmeier, C., Shahzamanian, B., Valencia-S, M., García-Marín, M., Horrobin, M., Moser, L., Zuther, J., Fischer, S., Rauch, C., Rost, S., Iserlohe, C., Yazici, S., Smajic, S., Wiest, M., Araujo-Hauck, C., Wank, I.: Beating the confusion limit: the necessity of high angular resolution for probing the physics of Sagittarius A* and its environment: opportunities for LINC-NIRVANA (LBT), GRAVITY (VLTI) and and METIS (E-ELT). In: Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, vol. 8445 (2012d). arXiv:1208.1129
[95] Einstein, A.: Lens-like action of a star by the deviation of light in the gravitational field. Science 84, 506-507 (1936) · Zbl 0015.27806 · doi:10.1126/science.84.2188.506
[96] Einstein, A.: On a stationary system with spherical symmetry consisting of many gravitating masses. Ann. Math. 40, 922 (1939) · Zbl 0023.42501 · doi:10.2307/1968902
[97] Eisenhauer, F., Schödel, R., Genzel, R., Ott, T., Tecza, M., Abuter, R., Eckart, A., Alexander, T.: A geometric determination of the distance to the galactic center. ApJL 597, L121-L124 (2003) · Zbl 1040.82027 · doi:10.1086/380188
[98] Eisenhauer, F., Genzel, R., Alexander, T., Abuter, R., Paumard, T., Ott, T., Gilbert, A., Gillessen, S., Horrobin, M., Trippe, S., Bonnet, H., Dumas, C., Hubin, N., Kaufer, A., Kissler-Patig, M., Monnet, G., Ströbele, S., Szeifert, T., Eckart, A., Schödel, R., Zucker, S.: SINFONI in the galactic center: young stars and infrared flares in the central light-month. ApJ 628, 246-259 (2005). arXiv:astro-ph/0502129
[99] Eisenhauer, F., Perrin, G., Brandner, W., Straubmeier, C., Richichi, A., Gillessen, S., Berger, J.P., Hippler, S., Eckart, A., Schöller, M., Rabien, S., Cassaing, F., Lenzen, R., Thiel, M., Clénet, Y., Ramos, J.R., Kellner, S., Fédou, P., Baumeister, H., Hofmann, R., Gendron, E., Boehm, A., Bartko, H., Haubois, X., Klein, R., Dodds-Eden, K., Houairi, K., Hormuth, F., Gräter, A., Jocou, L., Naranjo, V., Genzel, R., Kervella, P., Henning, T., Hamaus, N., Lacour, S., Neumann, U., Haug, M., Malbet, F., Laun, W., Kolmeder, J., Paumard, T., Rohloff, R.R., Pfuhl, O., Perraut, K., Ziegleder, J., Rouan, D., Rousset, G.: GRAVITY: getting to the event horizon of Sgr A*. In: Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, vol. 7013 (2008). arXiv:0808.0063
[100] Ellis, H.G.: Ether flow through a drainhole: a particle model in general relativity. J. Math. Phys. 14, 104-118 (1973) · doi:10.1063/1.1666161
[101] Emmanoulopoulos, D.: Pinpointing the base of the AGN jets through general relativistic X-ray reverberation studies. In: Massaro, F., Cheung, C.C., Lopez, E., Siemiginowska, A. (eds.) IAU Symposium, vol. 313, pp. 346-351 (2015). arXiv:1411.0727
[102] Esteban, E.P., Ramos, E.: Rotating black hole in an external electromagnetic field. Phys. Rev. D 38, 2963-2971 (1988) · doi:10.1103/PhysRevD.38.2963
[103] Ewing, E.A.: ’Black Holes’ in Space for Science S, the Public (edn) Science News Letters, January 18, p. 39 (1964)
[104] Falcke, H., Markoff, S.: The jet model for Sgr A*: radio and X-ray spectrum. A&A 362, 113-118 (2000)
[105] Falcke, H., Melia, F., Agol, E.: Viewing the shadow of the black hole at the galactic center. ApJL 528, L13-L16 (2000) · doi:10.1086/312423
[106] Falcke, H., Markoff, S., Bower, G.C.: Jet-lag in Sagittarius A*: what size and timing measurements tell us about the central black hole in the Milky Way. A&A 496, 77-83 (2009) · doi:10.1051/0004-6361/20078984
[107] Ferrarese, L., Côté, P., Dalla Bontà, E., Peng, E.W., Merritt, D., Jordán, A., Blakeslee, J.P., Haşegan, M., Mei, S., Piatek, S., Tonry, J.L., West, M.J.: A fundamental relation between compact stellar nuclei, supermassive black holes, and their host galaxies. ApJL 644, L21-L24 (2006). arXiv:astro-ph/0603840
[108] Ferré-Mateu, A., Mezcua, M., Trujillo, I., Balcells, M., van den Bosch, R.C.E.: Massive relic galaxies challenge the co-evolution of super-massive black holes and their host galaxies. ApJ 808, 79 (2015). arXiv:1506.02663
[109] Finkelstein, D.: Past-future asymmetry of the gravitational field of a point particle. Phys. Rev. 110(965), 110 (1958) · Zbl 0080.21701
[110] Fish, V.L., Doeleman, S.S., Beaudoin, C., Blundell, R., Bolin, D.E., Bower, G.C., Chamberlin, R., Freund, R., Friberg, P., Gurwell, M.A., Honma, M., Inoue, M., Krichbaum, T.P., Lamb, J., Marrone, D.P., Moran, J.M., Oyama, T., Plambeck, R., Primiani, R., Rogers, A.E.E., Smythe, D.L., SooHoo, J., Strittmatter, P., Tilanus, R.P.J., Titus, M., Weintroub, J., Wright, M., Woody, D., Young. K.H., Ziurys, L.M.: 1.3 mm wavelength VLBI of Sagittarius A*: detection of time-variable emission on event horizon scales. ApJL 727, L36 (2011)
[111] Fish, V.L., Johnson, M.D., Lu, R.S., Doeleman, S.S., Bouman, K.L., Zoran, D., Freeman, W.T., Psaltis, D., Narayan, R., Pankratius, V., Broderick, A.E., Gwinn, C.R., Vertatschitsch, L.E.: Imaging an event horizon: mitigation of scattering toward Sagittarius A*. ApJ 795, 134 (2014). arXiv:1409.4690
[112] Fish, V.L., Johnson, M.D., Doeleman, S.S., Broderick, A.E., Psaltis, D., Lu, R.S., Akiyama, K., Alef, W., Algaba, J.C., Asada, K., Beaudoin, C., Bertarini, A., Blackburn, L., Blundell, R., Bower, G.C., Brinkerink, C., Cappallo, R., Chael, A.A., Chamberlin, R., Chan, C.K., Crew, G.B., Dexter, J., Dexter, M., Dzib, S.A., Falcke, H., Freund, R., Friberg, P., Greer, C.H., Gurwell, M.A., Ho, P.T.P., Honma, M., Inoue, M., Johannsen, T., Kim, J., Krichbaum, T.P., Lamb, J., León-Tavares, J., Loeb, A., Loinard, L., MacMahon, D., Marrone, D.P., Moran, J.M., Mościbrodzka, M., Ortiz-León, G.N., Oyama, T., Özel, F., Plambeck, R.L., Pradel, N., Primiani, R.A., Rogers, A.E.E., Rosenfeld, K., Rottmann, H., Roy, A.L., Ruszczyk, C., Smythe, D.L., SooHoo, J., Spilker, J., Stone, J., Strittmatter, P., Tilanus, R.P.J., Titus, M., Vertatschitsch, L., Wagner, J., Wardle, J.F.C., Weintroub, J., Woody, D., Wright, M., Yamaguchi, P., Young, A., Young, K.H., Zensus, J.A., Ziurys, L.M.: Persistent asymmetric structure of Sagittarius A* on event horizon scales. ApJ 820, 90 (2016) · doi:10.3847/0004-637X/820/2/90
[113] Francis, C., Anderson, E.: Two estimates of the distance to the Galactic Centre. MNRAS 441, 1105-1114 (2014) · doi:10.1093/mnras/stu631
[114] Franklin, A.: What Makes a Good Experiment? University of Pittsburgh Press, Pittsburgh (2016). ISBN-13 9780822944416
[115] Freitag, M.: Gravitational waves from stars orbiting the Sagittarius A* black hole. Astrophys. J. Lett. 583(1), L21 (2003) · doi:10.1086/367813
[116] Fritz, T.K., Gillessen, S., Dodds-Eden, K., Martins, F., Bartko, H., Genzel, R., Paumard, T., Ott, T., Pfuhl, O., Trippe, S., Eisenhauer, F., Gratadour, D.: GC-IRS13E—a puzzling association of three early-type stars. ApJ 721, 395-411 (2010). arXiv:1003.1717
[117] Gair, J.R., Barack, L., Creighton, T., Cutler, C., Larson, S.L., Phinney, E.S., Vallisneri, M.: Event rate estimates for LISA extreme mass ratio capture sources. Class. Quantum Gravity 21, S1595-S1606 (2004) · Zbl 1170.83358 · doi:10.1088/0264-9381/21/20/003
[118] Gair, J.R., Vallisneri, M., Larson, S.L., Baker, J.G.: Testing general relativity with low-frequency, space-based gravitational-wave detectors. Liv. Rev. Relat. 16, 7 (2013) · doi:10.12942/lrr-2013-7
[119] Galison, P.: How Experiments End. The University of Chicago Press, Chicago (1987). ISBN: 9780226279152
[120] García Díaz, A.: Magnetic generalization of the Kerr-Newman metric. J. Math. Phys. 26, 155-156 (1985) · doi:10.1063/1.526777
[121] Genzel, R., Pichon, C., Eckart, A., Gerhard, O.E., Ott, T.: Stellar dynamics in the Galactic Centre: proper motions and anisotropy. MNRAS 317, 348-374 (2000). arXiv:astro-ph/0001428
[122] Genzel, R., Schödel, R., Ott, T., Eckart, A., Alexander, T., Lacombe, F., Rouan, D., Aschenbach, B.: Near-infrared flares from accreting gas around the supermassive black hole at the Galactic Centre. Nature 425, 934-937 (2003). arXiv:astro-ph/0310821
[123] Genzel, R., Eisenhauer, F., Gillessen, S.: The Galactic Center massive black hole and nuclear star cluster. Rev. Mod. Phys. 82, 3121-3195 (2010) arXiv:1006:0064
[124] Ghez, A., Morris, M., Lu, J., Weinberg, N., Matthews, K., Alexander, T., Armitage, P., Becklin, E., Brown, W., Campbell, R., Do, T., Eckart, A., Genzel, R., Gould, A., Hansen, B., Ho, L., Lo, F., Loeb, A., Melia, F., Merritt, D., Milosavljevic, M., Perets, H., Rasio, F., Reid, M., Salim, S., Schödel, R., Yelda, S.: The galactic center: a laboratory for fundamental astrophysics and galactic nuclei. In: astro2010: The Astronomy and Astrophysics Decadal Survey, Astronomy (2009). arXiv:0903.0383
[125] Ghez, A.M., Klein, B.L., Morris, M., Becklin, E.E.: High proper-motion stars in the vicinity of Sagittarius A*: evidence for a supermassive black hole at the center of our galaxy. ApJ 509, 678-686 (1998). arXiv:astro-ph/9807210
[126] Ghez, A.M., Duchene, G., Morris, M., Becklin, E.E., Hornstein, S.D., Tanner, A., Kremenek, T., Matthews, K., Thompson, D., Soifer, B.T., Larkin, J., McLean, I.: Full 3-D orbital solutions for stars making a close approach to the supermassive black hole at the center of the galaxy. In: American Astronomical Society Meeting Abstracts, Bulletin of the American Astronomical Society, vol. 34, p. 1219 (2002)
[127] Ghez, A.M., Wright, S.A., Matthews, K., Thompson, D., Le Mignant, D., Tanner, A., Hornstein, S.D., Morris, M., Becklin, E.E., Soifer, B.T.: Variable infrared emission from the supermassive black hole at the Center of the Milky Way. ApJL 601, L159-L162 (2004). arXiv:astro-ph/0309076
[128] Ghez, A.M., Salim, S., Weinberg, N.N., Lu, J.R., Do, T., Dunn, J.K., Matthews, K., Morris, M.R., Yelda, S., Becklin, E.E., Kremenek, T., Milosavljevic, M., Naiman, J.: Measuring distance and properties of the Milky Way’s central supermassive black hole with stellar orbits. ApJ 689, 1044-1062 (2008) · doi:10.1086/592738
[129] Ghisellini, G., Foschini, L., Volonteri, M., Ghirlanda, G., Haardt, F., Burlon, D., Tavecchio, F.: The blazar S5 0014+813: a real or apparent monster? MNRAS 399, L24-L28 (2009). arXiv:0906.0575
[130] Ghisellini, G., Della Ceca, R., Volonteri, M., Ghirlanda, G., Tavecchio, F., Foschini, L., Tagliaferri, G., Haardt, F., Pareschi, G., Grindlay, J.: Chasing the heaviest black holes of jetted active galactic nuclei. MNRAS 405, 387-400 (2010). arXiv:0912.0001
[131] Giannios, D., Lorimer, D.R.: Flares from Galactic Centre pulsars: a new class of X-ray transients? MNRAS 459, L95-L99 (2016) · doi:10.1093/mnrasl/slw041
[132] Giddings, S.B.: Possible observational windows for quantum effects from black holes. Phys. Rev. D 90(12), 124033 (2014). arXiv:1406.7001
[133] Gillessen, S., Eisenhauer, F., Quataert, E., Genzel, R., Paumard, T., Trippe, S., Ott, T., Abuter, R., Eckart, A., Lagage, P.O., Lehnert, M.D., Tacconi, L.J., Martins, F.: Variations in the Spectral Slope of Sagittarius A* during a Near-Infrared Flare. ApJL 640, L163-L166 (2006). arXiv:astro-ph/0511302
[134] Gillessen, S., Eisenhauer, F., Fritz, T.K., Bartko, H., Dodds-Eden, K., Pfuhl, O., Ott, T., Genzel, R.: The orbit of the star S2 Around SGR A* from very large telescope and keck data. ApJL 707, L114-L117 (2009a) · doi:10.1088/0004-637X/707/2/L114
[135] Gillessen, S., Eisenhauer, F., Trippe, S., Alexander, T., Genzel, R., Martins, F., Ott, T.: Monitoring stellar orbits around the massive black hole in the Galactic Center. ApJ 692, 1075-1109 (2009b) · doi:10.1088/0004-637X/692/2/1075
[136] Graham, A.W., Scott, N., Schombert, J.M.: Super-massive black hole mass scaling relations. Publ. Kor. Astron. Soc. 30, 335-339 (2015). arXiv:1411.1438
[137] Grenzebach, A., Perlick, V., Lämmerzahl, C.: Photon regions and shadows of accelerated black holes. Int. J. Mod. Phys. D 24, 1542024 (2015) · Zbl 1339.83044 · doi:10.1142/S0218271815420249
[138] Guedes, J., Madau, P., Mayer, L., Callegari, S.: Recoiling massive black holes in gas-rich galaxy mergers. ApJ 729, 125 (2011). arXiv:1008.2032 · Zbl 1025.83503
[139] Gwinn, C.R., Kovalev, Y.Y., Johnson, M.D., Soglasnov, V.A.: Discovery of Substructure in the Scatter-broadened Image of Sgr A*. ApJL 794, L14 (2014). arXiv:1409.0530
[140] Hacking, I. (ed.): Representing and Intervening, p. 24. Cambridge University Press, Cambridge (1983)
[141] Hacking, I.: Extragalactic reality: the case of gravitational lensing. Philos. Sci. 56, 555-581 (1989) · doi:10.1086/289514
[142] Haggard, H.M., Rovelli, C.: Quantum-gravity effects outside the horizon spark black to white hole tunneling. Phys. Rev. D 92(10), 104020 (2015) · doi:10.1103/PhysRevD.92.104020
[143] Hawking, S.: Information preservation and waether forcasting for black holes (2014). arXiv:1401.5761
[144] Hawking, S., Penrose, R.: The Nature of Space and Time. Princeton University Press, Princeton (1996) · Zbl 0962.83500
[145] Hawking, S.W., Israel, W.: Three Hundred Years of Gravitation. Cambridge University Press, Cambridge (1987) · Zbl 0645.53043
[146] Herdeiro, C.A.R., Radu, E.: Kerr black holes with scalar hair. Phys. Rev. Lett. 112(22), 221101 (2014). arXiv:1403.2757 · Zbl 1366.83035
[147] Heusler, M.: Black Hole Uniqueness Theorems. Cambridge University Press, Cambridge (1996) · Zbl 0945.83001 · doi:10.1017/CBO9780511661396
[148] Hoefer, C., Smeenk, C.: Philosophy of the physical sciences. In: Humphreys, P. (ed.) Oxford Handbook of the Philosophy of Science. Oxford University Press, Oxford (2016)
[149] Hopman, C., Alexander, T.: Resonant relaxation near a massive black hole: the stellar distribution and gravitational wave sources. ApJ 645, 1152-1163 (2006) · doi:10.1086/504400
[150] Horrobin, M., Eisenhauer, F., Tecza, M., Thatte, N., Genzel, R., Abuter, R., Iserlohe, C., Schreiber, J., Schegerer, A., Lutz, D., Ott, T., Schödel, R.: First results from SPIFFI. I: the galactic center. Astron. Nachr. 325, 88-91 (2004) · doi:10.1002/asna.200310181
[151] Hughes, S.A.: Evolution of circular, nonequatorial orbits of Kerr black holes due to gravitational-wave emission. Phys. Rev. D 61(8), 084004 (2000) · doi:10.1103/PhysRevD.61.084004
[152] Hughes, S.A.: Evolution of circular, nonequatorial orbits of Kerr black holes due to gravitational-wave emission. II. Inspiral trajectories and gravitational waveforms. Phys. Rev. D 64(6), 064004 (2001) · doi:10.1103/PhysRevD.64.064004
[153] Israel, W.: Dark stars: the evolution of an idea. In: Hawking, S.W., Israel, W. (eds.) Three Hundred Years of Gravitation, pp. 199-276 (1987) · Zbl 0966.83504
[154] Iwata, K., Yamazaki, S., Mutombo, P., Hapala, P., Ondráček, M., Jelínek, P., Sugimoto, Y.: Chemical structure imaging of a single molecule by atomic force microscopy at room temperature. Nat. Commun. 6, 7766 (2015) · doi:10.1038/ncomms8766
[155] Jaroszynski, M.: Prospects for the Determination of Star Orbits near the Galactic Center. ApJ 521, 591-596 (1999). arXiv:astro-ph/9903354
[156] Johannsen, T.: Sgr A* and general relativity. (2015) arXiv:1512.03818
[157] Johannsen, T.: Testing the no-hair theorem with observations of black holes in the electromagnetic spectrum. Class. Quantum Gravity 33(12), 124001 (2016). arXiv:1602.07694
[158] Johnson, M.D., Fish, V.L., Doeleman, S.S., Marrone, D.P., Plambeck, R.L., Wardle, J.F.C., Akiyama, K., Asada, K., Beaudoin, C., Blackburn, L., Blundell, R., Bower, G.C., Brinkerink, C., Broderick, A.E., Cappallo, R., Chael, A.A., Crew, G.B., Dexter, J., Dexter, M., Freund, R., Friberg, P., Gold, R., Gurwell, M.A., Ho, P.T.P., Honma, M., Inoue, M., Kosowsky, M., Krichbaum, T.P., Lamb, J., Loeb, A., Lu, R.S., MacMahon, D., McKinney, J.C., Moran, J.M., Narayan, R., Primiani, R.A., Psaltis, D., Rogers, A.E.E., Rosenfeld, K., SooHoo, J., Tilanus, R.P.J., Titus, M., Vertatschitsch, L., Weintroub, J., Wright, M., Young, K.H., Zensus, J.A., Ziurys, L.M.: Resolved magnetic-field structure and variability near the event horizon of Sagittarius A*. Science 350, 1242-1245 (2015). arXiv:1512.01220
[159] Karas, V., Vokrouhlický, D.: On interpretation of the magnetized Kerr-Newman black hole. J. Math. Phys. 32, 714-716 (1991) · Zbl 0729.53503 · doi:10.1063/1.529360
[160] Karas, V., Huré, J.M., Semerák, O.: TOPICAL REVIEW: Gravitating discs around black holes. Classical and Quantum Gravity 21, 1 (2004). arXiv:astro-ph/0401345 · Zbl 1054.83002
[161] Karas, V., Kopáček, O., Kunneriath, D.: Influence of frame-dragging on magnetic null points near rotating black holes. Class. Quantum Gravity 29(3), 035010 (2012). arXiv:1201.0009 · Zbl 1235.83061
[162] Kardashev, N.S., Andreyanov, V.V., Gromov, V.D., Buyakas, V.I., Gvamichava, A.S., Kotik, A.N., Kurt, V.G., Lazareva, G.S., Mironova, E.N., Myshonkova, N.V., Slysh, V.I., Trubnikov, A.G., Vinogradov, I.S., Troitsky, V.F., Puryaev, D.T., Usyukin, V.I.: The millimetron project. In: Kardashev, N.S., Dagkesamanskii, S.A. (eds.) Radioastronomical Tools and Techniques, p 111 (2007)
[163] Kardashev, N.S., Novikov, I.D., Lukash, V.N., Pilipenko, S.V., Mikheeva, E.V., Bisikalo, D.V., Wiebe, D.S., Doroshkevich, A.G., Zasov, A.V., Zinchenko, I.I., Ivanov, P.B., Kostenko, V.I., Larchenkova, T.I., Likhachev, S.F., Malov, I.F., Malofeev, V.M., Pozanenko, A.S., Smirnov, A.V., Sobolev, A.M., Cherepashchuk, A.M., Shchekinov, Y.A.: Review of scientific topics for the Millimetron space observatory. Phys. Usp. 57, 1199-1228 (2014) · doi:10.3367/UFNe.0184.201412c.1319
[164] Kaup, D.J.: Klein-Gordon geon. Phys. Rev. 172, 1331-1342 (1968) · doi:10.1103/PhysRev.172.1331
[165] Kerr, R.P.: Gravitational field of a spinning mass as an example of algebraically special metrics. Phys. Rev. Lett. 11, 237-238 (1963) · Zbl 0112.21904 · doi:10.1103/PhysRevLett.11.237
[166] Kiefer, C.: Thermodynamics of black holes and Hawking radiation. In: Fré, P., Gorini, V., Magli, G., Moschella, U. (eds.) Classical and Quantum Black Holes, pp. 17-74. Institute of Physics Publishing, Bristol (1999) · Zbl 0962.83023
[167] Kiefer, C.: Quantum Gravity, 3rd edn. Oxford University Press, Oxford (2012) · Zbl 1243.83002
[168] Kiefer, C.: Quantum black hole without singularity. In: BH6 Session at the Marcel Grossmann Conference MG14 on General Relativity and Quantum Cosmology, WSPC Proceedings (2015). arXiv:1512.08346
[169] Kiefer, C., Marto, J., Moniz, P.V.: Indefinite oscillators and black hole evaporation. Ann. Phys. (Berlin) 18, 722 (2009) · Zbl 1180.83056
[170] King, A.: How big can a black hole grow? MNRAS 456, L109-L112 (2016) · Zbl 1002.83053 · doi:10.1093/mnrasl/slv186
[171] Kiziltan, B., Baumgardt, H., Loeb, A.: An intermediate-mass black hole in the centre of the globular cluster 47 Tucanae. Nature 542, 203-205 (2017). arXiv:1702.02149
[172] Kormendy, J., Ho, L.C.: Coevolution (Or Not) of supermassive black holes and host galaxies. ARA&A 51, 511-653 (2013) · doi:10.1146/annurev-astro-082708-101811
[173] Krabbe, A., Genzel, R., Eckart, A., Najarro, F., Lutz, D., Cameron, M., Kroker, H., Tacconi-Garman, L.E., Thatte, N., Weitzel, L., Drapatz, S., Geballe, T., Sternberg, A., Kudritzki, R. The nuclear cluster of the milky way: star formation and velocity dispersion in the central 0.5 parsec. ApJL 447, L95 (1995)
[174] Laudan, L., Leplin, J.: Empirical equivalence and underdetermination larry laudan & jarrett leplin journal of philosophy 88 (9):449-472 (1991). J. Philos. 88, 449-472 (1991) · doi:10.2307/2026601
[175] Leinert, C., Graser, U.: MIDI: a mid-infrared interferometric instrument for the VLTI. In: Reasenberg, R.D. (ed) Astronomical Interferometry, Society of Photo-Optical Instrumentation Engineers (SPIE) Conference Series, vol. 3350, pp 389-393 (1998)
[176] Li, Z., Morris, M.R., Baganoff, F.K.: Evidence for a parsec-scale jet from the galactic center black hole: interaction with local gas. ApJ 779, 154 (2013) · doi:10.1088/0004-637X/779/2/154
[177] Löckmann, U., Baumgardt, H.: Tracing intermediate-mass black holes in the Galactic Centre. MNRAS 384, 323-330 (2008). arXiv:0711.1326
[178] Lu, R.S., Roelofs, F., Fish, V.L., Shiokawa, H., Doeleman, S.S., Gammie, C.F., Falcke, H., Krichbaum, T.P., Zensus, J.A.: Imaging an event horizon: mitigation of source variability of Sagittarius A*. ApJ 817 173 (2016). arXiv:1512.08543
[179] Lu, Y., Torres, D.F.: The Relativistic Iron \[K\alpha\] α Line from an Accretion Disc Onto a Static Non-Baryonic Compact Object. International Journal of Modern Physics D 12, 63-77 (2003). arXiv:astro-ph/0205418
[180] Luminet, J.P.: Image of a spherical black hole with thin accretion disk. A&A 75, 228-235 (1979)
[181] Maillard, J.P., Paumard, T., Stolovy, S.R., Rigaut, F.: The nature of the Galactic Center source IRS 13 revealed by high spatial resolution in the infrared. A&A 423, 155-167 (2004) · doi:10.1051/0004-6361:20034147
[182] Majaess, D.J., Turner, D.G., Lane, D.J.: Characteristics of the galaxy according to cepheids. MNRAS 398, 263-270 (2009) · doi:10.1111/j.1365-2966.2009.15096.x
[183] Malkin, Z.M.: Analysis of determinations of the distance between the sun and the galactic center. Astron. Rep. 57, 128-133 (2013) · doi:10.1134/S1063772913020078
[184] Maoz, E.: Dynamical constraints on alternatives to supermassive black holes in galactic nuclei. ApJL 494, L181-L184 (1998). arXiv:astro-ph/9710309
[185] Marcus, R.: The eleatic and the indispensabilist. THEORIA 30(3), 415-429 (2015) · Zbl 1375.00052 · doi:10.1387/theoria.12009
[186] Markakis, K., Dierkes, J., Eckart, A., Nishiyama, S., Britzen, S., García-Marín, M., Horrobin, M., Muxlow, T., Zensus, J.A.: Subaru and e-Merlin observations of NGC 3718. Diaries of a supermassive black hole recoil? A&A 580, A11 (2015) · doi:10.1051/0004-6361/201425077
[187] Markoff, S.: Sagittarius A* in context: daily flares as a probe of the fundamental X-ray emission process in accreting black holes. ApJL 618, L103-L106 (2005) · doi:10.1086/427841
[188] Markoff, S., Bower, G.C., Falcke, H.: How to hide large-scale outflows: size constraints on the jets of Sgr A*. MNRAS 379, 1519-1532 (2007) · doi:10.1111/j.1365-2966.2007.12071.x
[189] Markoff, S., Nowak, M.A., Maitra, D., Wilms, J., Gallo, E., Hynes, R., Plotkin, R.: Fitting along the fundamental plane: new comparisons of jet physics across the black hole mass scale. In: Romero, G.E., Sunyaev, R.A., Belloni, T. (eds.) Jets at All Scales, IAU Symposium, vol. 275, pp. 250-254 (2011)
[190] Matsuoka, Y., Strauss, M.A., Shen, Y., Brandt, W.N., Greene, J.E., Ho, L.C., Schneider, D.P., Sun, M., Trump, J.R.: The sloan digital sky survey reverberation mapping project: post-starburst signatures in quasar host galaxies at z \[{<}< 1\]. ApJ 811, 91 (2015). arXiv:1506.07535
[191] Mazur, P.O., Mottola, E.: Gravitational condensate stars: an alternative to black holes. ArXiv General Relativity and Quantum Cosmology arXiv:gr-qc/0109035 (2001) · Zbl 1242.83067
[192] Melia, F., Falcke, H.: The supermassive black hole at the galactic center. ARA&A 39, 309-352 (2001) · doi:10.1146/annurev.astro.39.1.309
[193] Menten, K.M., Reid, M.J., Eckart, A., Genzel, R.: The position of Sagittarius A*: accurate alignment of the radio and infrared reference frames at the galactic center. ApJL 475, L111-L114 (1997) · doi:10.1086/310472
[194] Merritt, D.: The distribution of stars and stellar remnants at the Galactic Center. ApJ 718, 739-761 (2010). arXiv:0909.1318
[195] Merritt, D., Alexander, T., Mikkola, S., Will, C.M.: Testing properties of the Galactic center black hole using stellar orbits. Phys. Rev. D 81(6), 062002 (2010) · doi:10.1103/PhysRevD.81.062002
[196] Meyer, L., Schödel, R., Eckart, A., Karas, V., Dovčiak, M., Duschl, W.J.: K-band polarimetry of an Sgr A* flare with a clear sub-flare structure. A&A 458, L25-L28 (2006) · doi:10.1051/0004-6361:20066251
[197] Meyer, L., Schödel, R., Eckart, A., Duschl, W.J., Karas, V., Dovčiak, M.: On the orientation of the Sagittarius A* system. A&A 473, 707-710 (2007) · doi:10.1051/0004-6361:20078009
[198] Mielke, E.W., Schunck, F.E.: Boson stars: alternatives to primordial black holes? Nucl. Phys. B 564, 185-203 (2000) arXiv:gr-qc/0001061
[199] Mielke, E.W., Schunck, F.E.: Boson and Axion Stars. In: Gurzadyan, V.G., Jantzen, R.T., Ruffini, R. (ed.). The Ninth Marcel Grossmann Meeting, pp. 581-591 (2002) · Zbl 1046.83022
[200] Miller, J.M., Tomsick, J.A., Bachetti, M., Wilkins, D., Boggs, S.E., Christensen, F.E., Craig, W.W., Fabian, A.C., Grefenstette, B.W., Hailey, C.J., Harrison, F.A., Kara, E., King, A.L., Stern, D.K., Zhang, W.W.: New constraints on the black hole low/hard state inner accretion flow with NuSTAR. ApJL 799, L6 (2015). arXiv:1411.1921
[201] Miller, M.C.: Constraints on alternatives to supermassive black holes. MNRAS 367, L32-L36 (2006). arXiv:astro-ph/0512194
[202] Misner, C., Thorne, K., Wheeler, J.: Gravitation. W. H. Freeman, San Francisco (1973). ISBN 978-0-7167-0344-0
[203] Montero, B.: Varieties of causal closure. In: Walter, S., Heckmann, H.-D. (eds.) Physicalism and Mental Causation: The Metaphysics of Mind and Action, Chapt. 8. Imprint Academic, Charlottesville, VA (2003). ISBN 0907845460
[204] Mori, K., Gotthelf, E.V., Zhang, S., An, H., Baganoff, F.K., Barrière, N.M., Beloborodov, A.M., Boggs, S.E., Christensen, F.E., Craig, W.W., Dufour, F., Grefenstette, B.W., Hailey, C.J., Harrison, F.A., Hong, J., Kaspi, V.M., Kennea, J.A., Madsen, K.K., Markwardt, C.B., Nynka, M., Stern, D., Tomsick, J.A., Zhang, W.W.: NuSTAR discovery of a 3.76 s transient magnetar near Sagittarius A*. ApJL 770, L23 (2013). arXiv:1305.1945
[205] Morris, M.; Howard, C.; Muno, M.; Baganoff, FK; Park, S.; Feigelson, E.; Garmire, G.; Brandt, N.; Pfalzner, S. (ed.); Kramer, C. (ed.); Staubmeier, C. (ed.); Heithausen, A. (ed.), The hot interstellar medium of the galactic center: observations with Chandra (2004), Berlin
[206] Mościbrodzka, M., Falcke, H.: Coupled jet-disk model for Sagittarius A*: explaining the flat-spectrum radio core with GRMHD simulations of jets. A&A 559, L3 (2013) · doi:10.1051/0004-6361/201322692
[207] Mościbrodzka, M., Falcke, H., Shiokawa, H., Gammie, C.F.: Observational appearance of inefficient accretion flows and jets in 3D GRMHD simulations: application to Sagittarius A*. A&A 570, A7 (2014) · doi:10.1051/0004-6361/201424358
[208] Mossoux, E., Grosso, N., Vincent, F.H., Porquet, D.: Study of the X-ray activity of Sagittarius A* during the 2011 XMM-Newton campaign. A&A 573, A46 (2015) · doi:10.1051/0004-6361/201424682
[209] Mou, G., Yuan, F., Bu, D., Sun, M., Su, M.: Fermi Bubbles Inflated by Winds Launched from the Hot Accretion Flow in Sgr A*. ApJ 790, 109 (2014). arXiv:1403.2129
[210] Mou, G., Yuan, F., Gan, Z., Sun, M.: The accretion wind model of fermi bubbles. II. Radiation. ApJ 811, 37 (2015). arXiv:1505.00892
[211] Mužić, K., Eckart, A., Schödel, R., Meyer, L., Zensus, A.: First proper motions of thin dust filaments at the Galactic center. A&A 469, 993-1002 (2007) · doi:10.1051/0004-6361:20066265
[212] Mužić, K., Eckart, A., Schödel, R., Buchholz, R., Zamaninasab, M., Witzel, G.: Comet-shaped sources at the Galactic center. Evidence of a wind from the central 0.2 pc. A&A 521, A13 (2010) · doi:10.1051/0004-6361/200913087
[213] Nakamura, M., Asada, K.: The parabolic jet structure in M87 as a magnetohydrodynamic nozzle. ApJ 775, 118 (2013). arXiv:1308.1436
[214] Narayan, R., Yi, I., Mahadevan, R.: Explaining the spectrum of Sagittarius A \[^*\]∗ with a model of an accreting black hole. Nature 374, 623-625 (1995) · doi:10.1038/374623a0
[215] Narayan, R., Mahadevan, R., Grindlay, J.E., Popham, R.G., Gammie, C.: Advection-dominated accretion model of Sagittarius A \[^*\]∗: evidence for a black hole at the Galactic center. ApJ 492, 554-568 (1998) · doi:10.1086/305070
[216] Natarajan, P., Treister, E.: Is there an upper limit to black hole masses? MNRAS 393, 838-845 (2009). arXiv:0808.2813
[217] Nayakshin, S., Power, C., King, A.R.: The observed M-\[ \sigma\] σ relations imply that super-massive black holes grow by cold chaotic accretion. ApJ 753, 15 (2012). arXiv:1203.3450
[218] Neilsen, J., Markoff, S., Nowak, M.A., Dexter, J., Witzel, G., Barrière, N., Li, Y., Baganoff, F.K., Degenaar, N., Fragile, P.C., Gammie, C., Goldwurm, A., Grosso, N., Haggard, D.: The X-ray flux distribution of Sagittarius A* as seen by Chandra. ApJ 799, 199 (2015a) · doi:10.1088/0004-637X/799/2/199
[219] Neilsen, J., Markoff, S., Nowak, M.A., Dexter, J., Witzel, G., Barrière, N., Li, Y., Baganoff, F.K., Degenaar, N., Fragile, P.C., Gammie, C., Goldwurm, A., Grosso, N., Haggard, D.: The X-ray flux distribution of Sagittarius A* as Seen by Chandra. ApJ 799, 199 (2015b). arXiv:1412.3106
[220] Nelson, O.J.: Hume’s ’new scene of thought’ and the several faces of David Hume in the dialogues concerning natural religion; with a preface by Jeff Broome; University Press of America, New York (2010). ISBN 978-0-7618-4735-9
[221] Neugebauer, G., Meinel, R.: The Einsteinian gravitational field of the rigidly rotating disk of dust. ApJL 414, L97-L99 (1993) · Zbl 0797.35157 · doi:10.1086/187005
[222] Newmann, A.: The correspondence theory of truth; an essay on the metaphysics of predication; part of Cambridge studies in philosophy. University of Nebraska, Omaha (2002). ISBN: 9780521811392
[223] Nordström, G.: On the energy of the gravitation field in Einstein’s theory. K. Ned. Akad. Wet. Proc. Ser. B 20, 1238-1245 (1918)
[224] Oka, T., Mizuno, R., Miura, K., Takekawa, S.: Signature of an intermediate-mass black hole in the central molecular zone of our galaxy. ApJL 816, L7 (2016) · doi:10.3847/2041-8205/816/1/L7
[225] Oppenheimer, J.R., Snyder, H.: On continued gravitational contraction. Phys. Rev. 56, 455-459 (1939) · Zbl 0022.28104 · doi:10.1103/PhysRev.56.455
[226] Oppenheimer, J.R., Volkoff, G.M.: On massive neutron cores. Phys. Rev. 55, 374-381 (1939) · Zbl 0020.28501 · doi:10.1103/PhysRev.55.374
[227] Ostriker, J.: The equilibrium of self-gravitating rings. ApJ 140, 1067 (1964) · doi:10.1086/148006
[228] de Oteyza, D., Gorman, P., et al.: Direct imaging of covalent bond structure in single-molecule chemical reactions. Science 340, 1434 (2013) · doi:10.1126/science.1238187
[229] Parsa, M., Eckart, A., et al.: Investigating relativistic motion of stars near the supermassive black hole in the Galactic center. A&A (2017, in preparation)
[230] Pasham, D.R., Strohmayer, T.E., Mushotzky, R.F.: A 400-solar-mass black hole in the galaxy M82. Nature 513, 74-76 (2014) · doi:10.1038/nature13710
[231] Paumard, T., Perrin, G., Eckart, A., Genzel, R., Lena, P., Schoedel, R., Eisenhauer, F., Mueller, T., Gillessen, S.: Scientific prospects for VLTI in the Galactic Centre: getting to the Schwarzschild radius. Astron. Nachr. 326, 568-568 (2005)
[232] Paumard, T., Perrin, G., Eckart, A., Genzel, R., Léna, P., Schödel, R., Eisenhauer, F., Müller, T., Gillessen, S.: Scientific prospects for VLTI in the Galactic Centre: getting to the Schwarzschild radius. In: Richichi, A., Delplancke, F., Paresce, F., Chelli, A. (eds.) The Power of Optical/IR Interferometry: Recent Scientific Results and 2nd Generation (2008)
[233] Peters, P.C., Mathews, J.: Gravitational radiation from point masses in a Keplerian orbit. Phys. Rev. 131, 435-440 (1963) · Zbl 0114.43902 · doi:10.1103/PhysRev.131.435
[234] Pierro, V., Pinto, I.M., Spallicci, A.D., Laserra, E., Recano, F.: Fast and accurate computational tools for gravitational waveforms from binary stars with any orbital eccentricity. MNRAS 325, 358-372 (2001). arXiv:gr-qc/0005044
[235] Plewa, P.M., Gillessen, S., Eisenhauer, F., Ott, T., Pfuhl, O., George, E., Dexter, J., Habibi, M., Genzel, R., Reid, M.J., Menten, K.M.: Pinpointing the near-infrared location of SgrA* by correcting optical distortion in the NACO imager. MNRAS 453, 3234-3244 (2015). doi:10.1093/mnras/stv1910
[236] Poisson, E.: A Relativist’s Toolkit—the Mathematics of Black-Hole Mechanics. A Relativist’s Toolkit—The Mathematics of Black-Hole Mechanics. Cambridge University Press, Cambridge (2004) · Zbl 1058.83002 · doi:10.1017/CBO9780511606601
[237] Pollney, D., Reisswig, C.: Gravitational memory in binary black hole mergers. ApJL 732, L13 (2011) arXiv:1004.4209 · Zbl 1222.83092
[238] Porquet, D., Grosso, N., Predehl, P., Hasinger, G., Yusef-Zadeh, F., Aschenbach, B., Trap, G., Melia, F., Warwick, R.S., Goldwurm, A., Bélanger, G., Tanaka, Y., Genzel, R., Dodds-Eden, K., Sakano, M., Ferrando, P.: X-ray hiccups from Sagittarius A* observed by XMM-Newton. The second brightest flare and three moderate flares caught in half a day. A&A 488, 549-557 (2008) · doi:10.1051/0004-6361:200809986
[239] Pott, J.U., Eckart, A., Glindemann, A., Viehmann, T., Schodel, R., Straubmeier, C., Leinert, C., Feldt, M., Genzel, R., Robberto, M.: VLTI Observations of IRS 3: The brightest compact MIR source at the Galactic Centre. Messenger 119, 43-44 (2005). arXiv:astro-ph/0505189
[240] Pott, J.U., Eckart, A., Glindemann, A., Schödel, R., Viehmann, T., Robberto, M.: The enigma of GCIRS 3. Constraining the properties of the mid-infrared reference star of the central parsec of the Milky Way with optical long-baseline interferometry. A&A 480, 115-131 (2008) · doi:10.1051/0004-6361:20066733
[241] Price, H.: Quining naturalism. J. Philos. 104, p375-p402 (2007) · doi:10.5840/jphil2007104812
[242] Psaltis, D.: The influence of gas dynamics on measuring the properties of the black hole in the center of the Milky Way with stellar orbits and pulsars. ApJ 759, 130 (2012). arXiv:1112.0026
[243] Psaltis, D., Narayan, R., Fish, V.L., Broderick, A.E., Loeb, A., Doeleman, S.S.: Event horizon telescope evidence for alignment of the black hole in the center of the Milky Way with the inner stellar disk. ApJ 798, 15 (2015) · doi:10.1088/0004-637X/798/1/15
[244] Psaltis, D., Wex, N., Kramer, M.: A quantitative test of the no-hair theorem with Sgr A* using stars, pulsars, and the event horizon telescope. ApJ 818, 121 (2016a). arXiv:1510.00394
[245] Psaltis, D., Wex, N., Kramer, M.: A quantitative test of the no-hair theorem with Sgr A* using stars, pulsars, and the event horizon telescope. ApJ 818, 121 (2016b). arXiv:1510.00394
[246] Psillos, S.: Living with the abstract: realism and models. Synthese 180, 3-17 (2011a) · doi:10.1007/s11229-009-9563-3
[247] Psillos, S.; Morgan, GJ (ed.), Making contact with molecules: on Perrin and Achinstein, 177-190 (2011), Oxford · doi:10.1093/acprof:oso/9780199738625.003.0014
[248] Quataert, E.: Radiatively Inefficient Accretion Flow Models of Sgr A*. Astron. Nachr. Suppl. 324, 435-443 (2003). arXiv:astro-ph/0304099
[249] Quine, W.: On what there is. Rev. Metaphys. 2(1948/1949), p21-38 (1948)
[250] Rauch, C., Ros, E., Krichbaum, T.P., Eckart, A., Zensus, J.A., Shahzamanian, B., Mužić, K.: Wisps in the Galactic center: near-infrared triggered observations of the radio source Sgr A* at 43 GHz. A&A 587, A37 (2016) · doi:10.1051/0004-6361/201527286
[251] Rees, M.J.: Black hole models for active galactic nuclei. ARA&A 22, 471-506 (1984) · doi:10.1146/annurev.aa.22.090184.002351
[252] Reid, M.J.: The distance to the center of the Galaxy. ARA&A 31, 345-372 (1993) · doi:10.1146/annurev.aa.31.090193.002021
[253] Reid, M.J., Menten, K.M., Genzel, R., Ott, T., Schödel, R., Brunthaler, A.: The position, motion, and mass of Sgr A*. Astron. Nachr. Suppl. 324, 505-511 (2003a) · doi:10.1002/asna.200385084
[254] Reid, M.J., Menten, K.M., Genzel, R., Ott, T., Schödel, R., Eckart, A.: The position of Sagittarius A*. II. Accurate positions and proper motions of stellar SiO masers near the Galactic Center. ApJ 587, 208-220 (2003b). arXiv:astro-ph/0212273
[255] Reissner, H.: Über die Eigengravitation des elektrischen Feldes nach der Einsteinschen Theorie. Ann. Phys. 355, 106-120 (1916) · doi:10.1002/andp.19163550905
[256] Renn, J., Sauer, T.: In the limelight of stars. Einstein, Mandl, and the origins of gravitational lens research (German Title: Im Rampenlicht der Sterne. Einstein, Mandl und die Ursprünge der Gravitationslinsenforschung). Acta Hist. Astron. 27, 210-239 (2005)
[257] Revnivtsev, M.G., Churazov, E.M., Sazonov, S.Y., Sunyaev, R.A., Lutovinov, A.A., Gilfanov, M.R., Vikhlinin, A.A., Shtykovsky, P.E., Pavlinsky, M.N.: Hard X-ray view of the past activity of Sgr A* in a natural Compton mirror. A&A 425, L49-L52 (2004) · doi:10.1051/0004-6361:200400064
[258] Reynolds, C.S.: Measuring black hole spin using X-ray reflection spectroscopy. Space Sci. Rev. 183, 277-294 (2014). arXiv:1302.3260
[259] Ricarte, A., Dexter, J.: The event horizon telescope: exploring strong gravity and accretion physics. MNRAS 446, 1973-1987 (2015) · doi:10.1093/mnras/stu2128
[260] Roedig, C., Sesana, A.: Origin and implications of high eccentricities in massive black hole binaries at sub-pc scales. J. Phys. Conf. Ser. 363(1), 012035 (2012). arXiv:1111.3742
[261] Rovelli, C., Vidotto, F.: Planck stars. Int. J. Mod. Phys. D 23, 1442026 (2014) · doi:10.1142/S0218271814420267
[262] Rozanska, A., Kunneriath, D., Czerny, B., Adhikari, T.P., Karas, V.: Multiphase environment of compact galactic nuclei: the role of the nuclear star cluster. MNRAS 464, 2090-2102 (2017) · doi:10.1093/mnras/stw2460
[263] Rubilar, G.F., Eckart, A.: Periastron shifts of stellar orbits near the Galactic Center. A&A 374, 95-104 (2001) · doi:10.1051/0004-6361:20010640
[264] Ruffini, R., Bonazzola, S.: Systems of self-gravitating particles in general relativity and the concept of an equation of state. Phys. Rev. 187, 1767-1783 (1969) · doi:10.1103/PhysRev.187.1767
[265] Sabha, N., Eckart, A., Merritt, D., Zamaninasab, M., Witzel, G., García-Marín, M., Jalali, B., Valencia-S, M., Yazici, S., Buchholz, R., Shahzamanian, B., Rauch, C., Horrobin, M., Straubmeier, C.: The S-star cluster at the center of the Milky Way. On the nature of diffuse NIR emission in the inner tenth of a parsec. A&A 545, A70 (2012) · doi:10.1051/0004-6361/201219203
[266] Sakai, N., Saida, H., Tamaki, T.: Gravastar shadows. Phys. Rev. D 90(10), 104013 (2014). arXiv:1408.6929
[267] Salpeter, E.E.: Accretion of interstellar matter by massive objects. ApJ 140, 796-800 (1964) · doi:10.1086/147973
[268] Sandell, M.: Astronomy and experimentation. Techné 14, 252-269 (2010)
[269] Schnittman, J.D.: Astrophysics of super-massive black hole mergers. Classical and Quantum Gravity 30(24), 244007 (2013). arXiv:1307.3542 · Zbl 1284.83010
[270] Schödel, R., Ott, T., Genzel, R., Hofmann, R., Lehnert, M., Eckart, A., Mouawad, N., Alexander, T., Reid, M.J., Lenzen, R., Hartung, M., Lacombe, F., Rouan, D., Gendron, E., Rousset, G., Lagrange, A.M., Brandner, W., Ageorges, N., Lidman, C., Moorwood, A.F.M., Spyromilio, J., Hubin, N., Menten, K.M.: A star in a 15.2-year orbit around the supermassive black hole at the centre of the Milky Way. Nature 419, 694-696 (2002) · doi:10.1038/nature01121
[271] Schödel, R., Eckart, A., Iserlohe, C., Genzel, R., Ott, T.: A black hole in the Galactic Center complex IRS 13E? ApJL 625, L111-L114 (2005). arXiv:astro-ph/0504474
[272] Schödel, R., Eckart, A., Alexander, T., Merritt, D., Genzel, R., Sternberg, A., Meyer, L., Kul, F., Moultaka, J., Ott, T., Straubmeier, C.: The structure of the nuclear stellar cluster of the Milky Way. A&A 469, 125-146 (2007) · doi:10.1051/0004-6361:20065089
[273] Schödel, R., Gallego-Cano, E., Dong, H., Nogueras-Lara, F., Gallego-Calvente, A.T., Amaro-Seoane, P., Baumgardt, H.: The distribution of stars around the Milky Way’s central black hole II: diffuse light from sub-giants and dwarfs. A&A (2017). arXiv:1701.03817
[274] Schwarzschild, K.: Über das Gravitationsfeld eines Massenpunktes nach der Einstein’schen Theorie (On the gravitational field of a mass point according to Einstein’s theory). Abh Königl Preuss Akad Wissenschaften, math-phys Klasse, 424 (1916). arXiv:physics/9912033 [physics.hist-ph] · Zbl 1210.83011
[275] Sellars, W.: Science, perception and reality. Ridgeview Publishing Company, Atascadero, CA (1963)
[276] Sesana, A., Gair, J., Berti, E., Volonteri, M.: Reconstructing the massive black hole cosmic history through gravitational waves. Phys. Rev. D 83(4), 044036 (2011). 1011.5893 · doi:10.1103/PhysRevD.83.044036
[277] Shahzamanian, B., Eckart, A., Valencia-S, M., Witzel, G., Zamaninasab, M., Sabha, N., García-Marín, M., Karas, V., Karssen, G.D., Borkar, A., Dovčiak, M., Kunneriath, D., Bursa, M., Buchholz, R., Moultaka, J., Straubmeier, C.: Polarized light from Sagittarius A* in the near-infrared \[K_s\] s-band. A&A 576, A20 (2015a) · doi:10.1051/0004-6361/201425239
[278] Shahzamanian, B., Eckart, A., Valencia-S, M., Witzel, G., Zamaninasab, M., Sabha, N., García-Marín, M., Karas, V., Karssen, G.D., Borkar, A., Dovčiak, M., Kunneriath, D., Bursa, M., Buchholz, R., Moultaka, J., Straubmeier, C.: Polarized light from Sagittarius A* in the near-infrared \[K_s\] s-band. A&A 576, A20 (2015b) · doi:10.1051/0004-6361/201425239
[279] Shapiro, S., Teukolsky, S.: Black Holes, White Dwarfs, and Neutron Stars: The Physics of Compact Objects. Wiley, New York (1983). ISBN 0-471-87317-9 · doi:10.1002/9783527617661
[280] Shcherbakov, R.V., Penna, R.F.: McKinney JC (2012) Sagittarius A* accretion flow and black hole parameters from general relativistic dynamical and polarized radiative modeling. ApJ 755, 133 (2012). arXiv:1007.4832
[281] Shen, Y., Greene, J.E., Ho, L.C., Brandt, W.N., Denney, K.D., Horne, K., Jiang, L., Kochanek, C.S., McGreer, I.D., Merloni, A., Peterson, B.M., Petitjean, P., Schneider, D.P., Schulze, A., Strauss, M.A., Tao, C., Trump, J.R., Pan, K., Bizyaev, D.: The sloan digital sky survey reverberation mapping project: no evidence for evolution in the M -\[ \sigma\] σ relation to z 1. ApJ 805, 96 (2015). arXiv:1502.01034
[282] Shen, Z.Q., Lo, K.Y., Liang, M.C., Ho, P.T.P., Zhao, J.H.: A size of \[\sim \]∼1AU for the radio source Sgr A* at the centre of the Milky Way. Nature 438, 62-64 (2005) · doi:10.1038/nature04205
[283] Slaný, P., Kovář, J., Stuchlík, Z., Karas, V.: Charged Tori in spherical gravitational and dipolar magnetic fields. ApJS 205, 3 (2013). arXiv:1302.2356
[284] Smeenk, C.; Eisenstaedt, J. (ed.); Kox, AJ (ed.), False vacuum: early universe cosmology and the development of inflation, No. 11 (2005), Boston · Zbl 1108.83004
[285] Spitler, L.G., Lee, K.J., Eatough, R.P., Kramer, M., Karuppusamy, R., Bassa, C.G., Cognard, I., Desvignes, G., Lyne, A.G., Stappers, B.W., Bower, G.C., Cordes, J.M., Champion, D.J., Falcke, H.: Pulse broadening measurements from the Galactic Center pulsar J1745-2900. ApJL 780, L3 (2014). arXiv:1309.4673
[286] Su, M., Slatyer, T.R., Finkbeiner, D.P.: Giant gamma-ray bubbles from fermi-LAT: active galactic nucleus activity or bipolar galactic wind? ApJ 724, 1044-1082 (2010). arXiv:1005.5480
[287] Sunyaev, R., Churazov, E.: Equivalent width, shape and proper motion of the iron fluorescent line emission from molecular clouds as an indicator of the illuminating source X-ray flux history. MNRAS 297, 1279-1291 (1998). arXiv:astro-ph/9805038
[288] Synge, J.L.: The escape of photons from gravitationally intense stars. MNRAS 131, 463 (1966) · doi:10.1093/mnras/131.3.463
[289] Terrier, R., Ponti, G., Bélanger, G., Decourchelle, A., Tatischeff, V., Goldwurm, A., Trap, G., Morris, M.R., Warwick, R.: Fading hard X-ray emission from the Galactic Center molecular cloud Sgr B2. ApJ 719, 143-150 (2010). arXiv:1005.4807
[290] The eLISA Consortium: Seoane PAea: The Gravitational Universe. (2013). arXiv:1305.5720
[291] The L.I.G.O. Scientific Collaboration; The Virgo Collaboration.: Properties of the binary black hole merger GW150914. (2016). arXiv:1602.03840
[292] Torres, D.F., Capozziello, S., Lambiase, G.: Supermassive boson stars: prospects for observational detection. (2000). ArXiv:gr-qc/0012031
[293] Trippe, S., Paumard, T., Ott, T., Gillessen, S., Eisenhauer, F., Martins, F., Genzel, R.: A polarized infrared flare from Sagittarius A* and the signatures of orbiting plasma hotspots. MNRAS 375, 764-772 (2007). arXiv:astro-ph/0611737
[294] Tsupko, O.Y., Bisnovatyi-Kogan, G.S.: Gravitational lensing in plasma: relativistic images at homogeneous plasma. Phys. Rev. D 87(12), 124009 (2013) · doi:10.1103/PhysRevD.87.124009
[295] van Fraassen, C.: Images of Science: Essays on Realism and Empiricism; Churchland, P.M. (ed.). University Of Chicago Press, Chicago (1985). ISBN-13: 978-0226106540
[296] Vanhollebeke, E., Groenewegen, M.A.T., Girardi, L.: Stellar populations in the Galactic bulge. Modelling the Galactic bulge with TRILEGAL. A&A 498, 95-107 (2009) · doi:10.1051/0004-6361/20078472
[297] Vasudevan, R.V., Fabian, A.C.: Piecing together the X-ray background: bolometric corrections for active galactic nuclei. MNRAS 381, 1235-1251 (2007) · doi:10.1111/j.1365-2966.2007.12328.x
[298] Verozub, L.: Sgr A* as probe of the theory of supermassive compact objects without event horizon. Astron. Nachr. 327, 355 (2006) · doi:10.1002/asna.200410534
[299] Vincent, F.H., Paumard, T., Perrin, G., Mugnier, L., Eisenhauer, F., Gillessen, S. (2011a) Astrometric study of the complex environment of Sgr A* in imaging mode with the VLTI/GRAVITY instrument. In: Morris, M.R., Wang, Q.D., Yuan, F. (eds.) The Galactic Center: A Window to the Nuclear Environment of Disk Galaxies, Astronomical Society of the Pacific Conference Series, vol. 439, p. 275
[300] Vincent, F.H., Paumard, T., Perrin, G., Mugnier, L., Eisenhauer, F., Gillessen, S.: Performance of astrometric detection of a hotspot orbiting on the innermost stable circular orbit of the Galactic Centre black hole. MNRAS 412, 2653-2664 (2011b). arXiv:1011.5439
[301] Vincent, F.H., Paumard, T., Perrin, G., Varniere, P., Casse, F., Eisenhauer, F., Gillessen, S., Armitage, P.J.: Distinguishing an ejected blob from alternative flare models at the Galactic Centre with GRAVITY. MNRAS 441, 3477-3487 (2014). arXiv:1404.6149
[302] Vincent, F.H., Meliani, Z., Grandclement, P., Gourgoulhon, E., Straub, O.: Imaging a boson star at the Galactic center. (2015). arXiv:1510.04170 · Zbl 1329.83058
[303] Viollier, R.D., Leimgruber, F.R., Trautmann, D.: Halos of heavy neutrinos around baryonic stars. Phys. Lett. B 297, 132-137 (1992) · doi:10.1016/0370-2693(92)91081-J
[304] Wald, R.: General Relativity. The University of Chicago Press, Chicago (1984). ISBN: 9780226870335 · Zbl 0549.53001
[305] Walker, S.A., Fabian, A.C., Russell, H.R., Sanders, J.S.: The effect of the quasar H1821+643 on the surrounding intracluster medium: revealing the underlying cooling flow. MNRAS 442, 2809-2816 (2014). arXiv:1405.7522
[306] Walsh, J.L., Barth, A.J., Ho, L.C., Sarzi, M.: The M87 black hole mass from gas-dynamical models of space telescope imaging spectrograph observations. ApJ 770, 86 (2013). arXiv:1304.7273
[307] Wang, X., Loeb, A.: Detecting floating black holes as they traverse the gas disc of the Milky Way. MNRAS 441, 809-812 (2014) · doi:10.1093/mnras/stu600
[308] Wharton, R.S., Chatterjee, S., Cordes, J.M., Deneva, J.S., Lazio, T.J.W.: Multiwavelength constraints on pulsar populations in the Galactic Center. ApJ 753, 108 (2012). arXiv:1111.4216
[309] Will, C.M.: Perturbation of a slowly rotating black hole by a stationary axisymmetric ring of matter. I. Equilibrium configurations. ApJ 191, 521-532 (1974) · doi:10.1086/152992
[310] Witzel, G., Eckart, A., Bremer, M., Zamaninasab, M., Shahzamanian, B., Valencia-S, M., Schödel, R., Karas, V., Lenzen, R., Marchili, N., Sabha, N., Garcia-Marin, M., Buchholz, R.M., Kunneriath, D., Straubmeier, C.: Source-intrinsic near-infrared properties of Sgr A*: total intensity measurements. ApJS 203, 18 (2012a) · doi:10.1088/0067-0049/203/2/18
[311] Witzel, G., Eckart, A., Bremer, M., Zamaninasab, M., Shahzamanian, B., Valencia-S, M., Schödel, R., Karas, V., Lenzen, R., Marchili, N., Sabha, N., Garcia-Marin, M., Buchholz, R.M., Kunneriath, D., Straubmeier, C.: Source-intrinsic near-infrared properties of Sgr A*: total intensity measurements. ApJS 203, 18 (2012b). arXiv:1208.5836
[312] Wollman, E.R., Geballe, T.R., Lacy, J.H., Townes, C.H., Rank, D.M.: NE II 12.8 micron emission from the galactic center. II. ApJL 218, L103-L107 (1977) · doi:10.1086/182585
[313] Wrobel, J.M., Miller-Jones, J.C.A., Middleton, M.J.: A very large array search for intermediate-mass black holes in globular clusters in M81. Astron. J. 152, 22 (2016) · doi:10.3847/0004-6256/152/1/22
[314] Wu, Q., Czerny, B., Grzedzielski, M., Janiuk, A., Gu, W.M., Aj, Dong, Cao, X.F., You, B., Yan, Z., Sun, M.Y.: The universal heartbeat; oscillations in black hole systems across the mass-scale. ApJ 833, 79 (2016) · Zbl 0112.21904
[315] Wyithe, J.S.B., Loeb, A.: Low-Frequency Gravitational Waves from Massive Black Hole Binaries: Predictions for LISA and Pulsar Timing Arrays. ApJ 590, 691-706 (2003). arXiv:astro-ph/0211556
[316] Yagi, K., Stein, L.C.: Black hole based tests of general relativity. Class. Quantum Gravity 33(5), 054001 (2016). arXiv:1602.02413 · Zbl 1338.83019
[317] Yuan, F., Narayan, R.: Hot accretion flows around black holes. ARA&A 52, 529-588 (2014) · doi:10.1146/annurev-astro-082812-141003
[318] Yuan, F., Quataert, E., Narayan, R.: Nonthermal electrons in radiatively inefficient accretion flow models of Sagittarius A*. ApJ 598, 301-312 (2003). arXiv:astro-ph/0304125
[319] Yuan, F., Bu, D., Wu, M.: Numerical simulation of hot accretion flows. II. Nature, origin, and properties of outflows and their possible observational applications. ApJ 761, 130 (2012) arXiv:1206.4173
[320] Yunes, N., Siemens, X.: Gravitational-wave tests of general relativity with ground-based detectors and pulsar-timing arrays. Liv. Rev. Relat. 16, 9 (2013) · doi:10.12942/lrr-2013-9
[321] Yusef-Zadeh, F., Wardle, M., Miller-Jones, J.C.A., Roberts, D.A., Grosso, N., Porquet, D.: Rapid intrinsic variability of SGR A* at radio wavelengths. ApJ 729, 44 (2011) · doi:10.1088/0004-637X/729/1/44
[322] Yusef-Zadeh, F., Arendt, R., Bushouse, H., Cotton, W., Haggard, D., Pound, M.W., Roberts, D.A., Royster, M., Wardle, M.: A 3 pc scale jet-driven outflow from Sgr A*. ApJL 758, L11 (2012a) · doi:10.1088/2041-8205/758/1/L11
[323] Yusef-Zadeh, F., Wardle, M., Dodds-Eden, K., Heinke, C.O., Gillessen, S., Genzel, R., Bushouse, H., Grosso, N., Porquet, D.: An inverse compton scattering origin of X-ray flares from Sgr A*. AJ 144, 1 (2012b) · doi:10.1088/0004-6256/144/1/1
[324] Yusef-Zadeh, F., Wardle, M., Cotton, W., Schödel, R., Royster, M.J., Roberts, D.A., Kunneriath, D.: Tidal distortion of the envelope of an AGB star IRS 3 near Sgr A*. (2017)
[325] Zajacek, M., Karas, V., Kunneriath, D.: Galactic Center minispiral: interaction modes of neutron stars. Acta Polytech. 55, 203-214 (2015) · doi:10.14311/AP.2015.55.0203
[326] Zakharov, A.F.: Constraints on a charge in the Reissner-Nordström metric for the black hole at the Galactic Center. Phys. Rev. D 90(6), 062007 (2014) · doi:10.1103/PhysRevD.90.062007
[327] Zamaninasab, M., Eckart, A., Witzel, G., Dovciak, M., Karas, V., Schödel, R., Gießübel, R., Bremer, M., García-Marín, M., Kunneriath, D., Mužić, K., Nishiyama, S., Sabha, N., Straubmeier, C., Zensus, A.: Near infrared flares of Sagittarius A*. Importance of near infrared polarimetry. A&A 510, A3 (2010) · doi:10.1051/0004-6361/200912473
[328] Zeh, H.D.: The Physical Basis of the Direction of Time, Fifth edn. Springer, Berlin (2007). ISBN 978-3-540-68000-0
[329] Zel’dovich, Y.B., Novikov, I.D.: The radiation of gravity waves by bodies moving in the field of a collapsing star. Sov. Phys. Dokl. 9, 246 (1964)
[330] Zubovas, K., Nayakshin, S., Markoff, S.: Sgr A* flares: tidal disruption of asteroids and planets? MNRAS 421, 1315-1324 (2012). arXiv:1110.6872
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